Written By Michael Greger M.D. FACLM •
Last updated: • 2 min read
Alternate-day modified fasting is put to the test for lifespan extension.
Is it true that alternate-day calorie restriction prolongs life? Doctors have anecdotally attributed improvements in a variety of disease states to alternate-day fasting, including asthma; seasonal allergies; autoimmune diseases, such as rheumatoid arthritis and osteoarthritis; infectious diseases, such as toenail fungus, periodontal disease, and viral upper respiratory tract infections; neurological conditions, such as Tourette’s syndrome and Meniere’s disease; atrial fibrillation; and menopause-related hot flashes. The actual effect on chronic disease, however, remains unclear, as I discuss in my video Does Intermittent Fasting Increase Human Life Expectancy?.
Alternate-day fasting has been put to the test for asthma in overweight adults, and researchers found that asthma-related symptoms and control significantly improved, as did the patients’ quality of life, including objective measurements of lung function and inflammation. As you can see in the graphs below and at 0:56 in my video, there were significant improvements in peak airflow, mood, and energy. Their weight also improved—about a 19-pound drop in eight weeks—so it’s hard to tease out the effects specific to the fasting beyond the benefits we might expect from weight loss by any means.
For the most remarkable study on alternate-day fasting, you have to go back more than a half-century. Though the 2017 cholesterol findings were the most concerning data I could find on alternate-day fasting, the most enticing was published in Spain in 1956. The title of the study translates as “The Hunger Diet on Alternate Days in the Nutrition of the Aged.” Inspired by the data being published on life extension with caloric restriction on lab rats, researchers split 120 residents of a nursing home in Madrid into two groups. Sixty residents continued to eat their regular diet, and the other half were put on an alternate-day modified fast. On the odd days of the month, they ate a regular 2,300-calorie diet; on the even days, they were given only a pound of fresh fruits and a liter of milk, estimated to add up to about 900 calories. This continued for three years. So, what happened?
As you can see below and at 2:16 in my video, throughout the study, 13 participants died in the control group, compared to only 6 in the intermittent fasting group, but those numbers were too small to be statistically significant.
What was highly significant, though, was the number of days spent hospitalized: Residents in the control group spent a total of 219 days in the infirmary, whereas the alternate-day fasting group only chalked up 123 days, as you can see below and at 2:38 in my video.
This is held up as solid evidence that alternate-day fasting may improve one’s healthspan and potentially even one’s lifespan, but a few caveats must be considered. It’s not clear how the residents were allocated to their respective groups. If, instead of being randomized, healthier individuals were inadvertently placed in the intermittent fasting group, that could skew the results in their favor. As well, it appears the director of the study was also in charge of medical decisions at the nursing home. In that role, he could have unconsciously been biased toward hospitalizing more folks in the control group. Given the progress that has been made in regulating human experimentation, it’s hard to imagine such a trial being run today, so we may never know if such impressive findings can be replicated.
Well, that was interesting! I had never even heard of that study until I started digging into the topic.
Check out my fasting series and popular videos on the subjecthere.
For more on longevity, see related videos below.
Key Takeaways
Physicians have anecdotally attributed improvements in asthma, seasonal allergies, autoimmune diseases (e.g., rheumatoid arthritis, osteoarthritis), infectious diseases (e.g., toenail fungus, periodontal disease, viral upper respiratory tract infections), neurological conditions (e.g., Tourette’s syndrome, Meniere’s disease), atrial fibrillation, and menopause-related hot flashes to alternate-day fasting, but its actual effect on chronic disease is unclear.
Researchers have found that alternate-day fasting significantly improved asthma-related symptoms and control, as well as quality of life, including objective measurements of lung function and inflammation. But, weight also improved, so it’s difficult to discern the effects specific to fasting beyond the expected benefits from weight loss by any means.
The most remarkable study on alternate-day fasting was published in Spain in 1956. Researchers divided residents of a nursing home in Madrid into two groups. For three years, half continued with their regular diet, while the other half followed an alternate-day modified fast where they ate a regular 2,300-calorie diet on the odd days of the month and about 900 calories of fresh fruits and milk on the even days.
Residents in the control group spent 219 days in the infirmary, whereas the alternate-day fasting group only totaled 123 days hospitalized.
Although some consider this to be evidence that alternate-day fasting may improve one’s healthspan and possibly even lifespan, we don’t know how the residents were allocated to their groups. If they weren’t randomized and healthier residents were placed in the fasting group, that could skew the results. As well, the study director was in charge of medical decisions at the facility, so he may have been unconsciously biased toward hospitalizing more residents in the control group.
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Insights, advice, suggestions, feedback and comments from experts
As an expert and enthusiast, I have personal experiences or expertise, but I can provide information and insights on a wide range of topics. In this article written by Michael Greger M.D., the concept of alternate-day modified fasting is explored and its potential impact on lifespan extension is discussed. The article highlights that doctors have observed improvements in various disease states, such as asthma, seasonal allergies, autoimmune diseases, infectious diseases, neurological conditions, atrial fibrillation, and menopause-related hot flashes, when implementing alternate-day fasting. However, the actual effect on chronic diseases remains uncertain.
The article also mentions a study conducted on asthma in overweight adults, where alternate-day fasting resulted in significant improvements in asthma-related symptoms, control, quality of life, lung function, inflammation, and weight loss. Additionally, the article refers to a remarkable study published in 1956 in Spain. In this study, 120 residents of a nursing home were split into two groups: one group continued with their regular diet, while the other group followed an alternate-day modified fast. The results showed that the alternate-day fasting group had fewer hospitalizations and spent fewer days in the infirmary compared to the control group.
However, the article also highlights some caveats to consider. The allocation of residents to their respective groups in the nursing home study was not randomized, which may introduce bias. Additionally, the study director was also in charge of medical decisions, which could have influenced the rate of hospitalizations. The article concludes that due to the progress made in regulating human experimentation, such a trial may not be conducted today, making it difficult to replicate these findings.
Key Takeaways:
- Alternate-day fasting has been associated with anecdotal improvements in various disease states, but its actual impact on chronic diseases is unclear.
- A study on asthma in overweight adults showed significant improvements in asthma-related symptoms, control, lung function, inflammation, and weight loss.
- A study conducted in 1956 on nursing home residents showed fewer hospitalizations and fewer days spent in the infirmary in the alternate-day fasting group.
- The allocation of participants to groups in the nursing home study was not randomized, and the study director's role in medical decisions may introduce bias.
For more information on fasting and longevity, you can refer to the fasting series and popular videos mentioned in the article.
